Joint, particularly a ball-and-socket joint for chassis parts in a motor vehicle

ABSTRACT

The present invention pertains to a joint ( 1 ) with a joint housing ( 2 ) and with a joint shell ( 3 ) arranged therein with a ball ( 4 ), whose pivot pin ( 5 ) protrudes from the joint housing ( 2 ) and is surrounded by a rubber bellows ( 6 ) with a protective cap ( 7 ), wherein a ring ( 8 ) for holding the protective cap ( 7 ) is connected to the edge area ( 6   a ) of the rubber bellows ( 6 ), which said edge area ( 6   a ) concentrically surrounds the pivot pin ( 5 ), and wherein the ring ( 8 ) has a circular bead ( 8   b,    8   c ) on its annular outer side ( 8   a ) and is vulcanized into the edge area ( 6   a ) of the rubber bellows ( 6 ), and the protective cap ( 7 ) is provided on its inner side ( 7   a ) with a plurality of projections ( 9 ), which can be bent from the outside through openings ( 10 ) in the protective cap ( 7 ) by means of a tool ( 11 ) radially (arrow  12 ) in relation to the pivot pin ( 5 ) against the bead ( 8   b,    8   c ) of the ring ( 8 ) in a non-positive and positive-locking manner.

[0001] The present invention pertains to a joint, especially aball-and-socket joint for chassis parts in a motor vehicle, with a jointhousing and a joint shell arranged therein with a ball, whose pivot pinprotrudes from the joint housing and is surrounded by a rubber bellowswith a protective cap, wherein a ring for holding the protective cap isconnected to the edge area of the rubber bellows, which said edge areaconcentrically surrounds the pivot pin.

[0002] A prior-art joint of this type according to U.S. Pat. No.5,100,254 has, among other things, a rubber bellows with a metal ring ofa U-shaped cross section, which is connected thereto and in the U-shapedrecess of which the lip of a protective cap consisting of plastic isclipped. Since the protective cap must be pushed against the rubberbellows downwardly in the direction of the longitudinal direction toclip this lip into the ring of the rubber bellows, the rubber bellows isinevitably subject to an undesired deformation, because an opposingpressing force with a counterpressure element is absent. Consequently,the protective cap with the compressed rubber bellows must be inevitablypulled in the opposite direction after the clipping, which may in turnlead to the release of the protective cap from the ring. At any rate, itis disadvantageous in the different embodiments according to thisdocument that the protective cap must always be pressed in the directionof the longitudinal axis towards the ball against the rubber bellows forconnection with the ring. An undesired deformation of the rubber bellowsis inevitable as a consequence of these axial forces.

[0003] A joint of a different class, which is surrounded by a protectivecap fastened to the joint housing of the ball-and-socket joint, hasbecome known from EP 0 570 736 A1. This protective cap is held in arecess extending circularly around the joint housing by means of aretaining ring. Even though this construction advantageously shields therubber bellows against lateral thermal effects like a heat shield, thepenetration of particles from the pivot side toward the rubber bellowscannot be prevented, because the necessary angular deflection of theball pivot inevitably determines the size of the non-shieldedintermediate space between it and the inner side of the protective cap.In addition, this construction requires two different fastenings,namely, for the rubber bellows, on the one hand, and for the protectiveshield, on the other hand.

[0004] Such heat insulation means are always needed wheneverball-and-socket joints are arranged in the vicinity of heat sources,e.g., disk brakes, without sufficient protection being provided forcooling or without other heat-insulating measures being able to betaken. Protective caps made of sheet metal have been known in thisconnection, which are arranged either at the steering knuckle, at thejoint housing of the ball pivot or at the suspension arm. They aremounted in the course of the mounting of the axle or the mounting of theindividual components. The drawback of all these solutions is basedespecially on their complicated and error-prone mounting or, in the caseof the solutions with arrangement at the joint housing, on the strongeffect of the movements of the joint on the possible enclosing angle ofthe sheet metal around the sealing bellows. Joints with a large angulardeflection can therefore be protected only insufficiently with thesolution according to EP 0 570 736 A1.

[0005] Protective caps made of plastic or rubber materials can withstandonly substantially lower peak temperatures than metal or, in the case ofrubber material, they may even be deformed by the relative wind of thevehicle and/or be subject to fluttering movements.

[0006] By contrast, caps made of metal or plastic, which are pressed onthe pivot pin, must be oriented during mounting in the vehicle and areassociated with the risk of becoming separated due to the short lengthover which they are pressed on.

[0007] To illustrate these problems, reference is made to the work ofProf. Jörnsen Reimpell, Cert. Eng., entitled “Chassis Engineering: WheelSuspensions,” 2nd edition, 1988, pp. 132 and 304, in which joints withprotective caps are shown on the front axle side of a motor vehicle.

[0008] Based on this state of the art, the basic object of the presentinvention is to improve a joint of the class mentioned in theintroduction such that while offering protection for the rubber bellowsover a large area, it can be manufactured and mounted in a simplemanner, without exposing the rubber bellows to appreciable axial forces.

[0009] This object is accomplished in conjunction with the generic termmentioned in the introduction, according to a first embodiment, by thering having at least one bead on its annular outer side and by beingvulcanized into the edge area of the rubber bellows, and by theprotective cap being provided on its inner side with a plurality ofprojections, which can be bent through openings in the protective cap inthe outward direction against the bead of the ring in a non-positive andpositive-locking manner. Thus, the deformation mentioned can be broughtabout, e.g., by means of a tool radially or centripetally in relation tothe pivot pin. For example, a screw driver would have to be passed forthis purpose through the opening in the protective cap and theprojection would have to be bent radially against the bead of the ringin order to guarantee the reliable and firm seating of the protectivecap on the ring vulcanized into the rubber bellows. Thus, theprojections become dug into the ring incorporated by vulcanization.

[0010] The ring advantageously has a plurality of beads and, e.g., alsobeads extending over the entire periphery in the cross section, so thatit forms a wave shape, whereas the protective cap completely surroundingthe rubber bellows is provided with T-shaped notches, of which at leastone web is bent off toward the inner side of the protective cap andforms a projection. As a result, the notch also forms an opening forpassing through a tool, e.g., a screw driver, in order to dig theprojection into the ring of the rubber bellows by bending.

[0011] According to a second embodiment, the basic object of the presentinvention is accomplished in conjunction with the generic term mentionedin the introduction by the ring being vulcanized into the edge area ofthe rubber bellows and having a plurality of projections on its sidefacing away from the ball-and-socket joint, which said projections passthrough the openings prepared in advance with identical cross-sectionalconfiguration in the protective cap and connect the ring to theprotective cap after passing through by a mechanical or thermaldeformation. In this embodiment, the protective cap with its openings isslipped over the projections of the vulcanized ring of the rubberbellows and these projections are then either bent over radially bymeans of a suitable tool or, if the projections consist of a plastic,they are provided with a broader head by a moderate and short-termheating, e.g., by thermal melting, and the protective cap is thusinseparably connected to the rubber bellows. The protective capsurrounds the rubber bellows without interruptions according to thissolution because the openings according to the first solution are notnecessary for passing through a tool.

[0012] According to an advantageous variant of the present invention,the projections of the ring are formed by teeth of equal size, which arearranged at equally spaced locations and pass through a correspondinghole pattern of the protective cap when the latter is put on.Appreciable axial forces cannot be encountered in this case, either, andradial forces are also unnecessary during the melting of projectionsconsisting of, e.g., a plastic.

[0013] The rings advantageously consist of a metal or plastic such as PA66. The ring provided with a bead advantageously consists of hardenedcarbon steel.

[0014] The ring provided with the projections in the rubber bellows ismade either of metal or a plastic with high heat resistance, e.g., PA66, PTFE or PEEK. The protective cap should keep both thermal andmechanical effects away from the rubber bellows and should therefore bemade of special steel, hot-galvanized steel plate or a glassfiber-reinforced plastic.

[0015] A plurality of exemplary embodiments of the present invention areshown in the drawings. In the figures,

[0016]FIGS. 1a through 1 c show the individual phases of the firstsolution for connecting a protective cap to a rubber bellows, namely,

[0017]FIG. 1b shows the perspective view of a ball-and-socket jointwithout rubber bellows and protective cap,

[0018]FIG. 1b shows the view from FIG. 1a with a rubber bellows pushedover the pivot pin with the ring vulcanized in,

[0019]FIG. 1c shows the view according to FIG. 1b with a protective capconnected to the rubber bellows,

[0020]FIG. 2 shows the perspective sectional view in the direction ofarrows II-II in FIG. 1c in an enlarged view compared with FIG. 1c,

[0021]FIG. 3 shows the enlarged detail III from FIG. 2,

[0022]FIG. 4 shows the diametric sectional view through the rubberbellows with the ring vulcanized in,

[0023]FIG. 5 shows the enlarged detail V from FIG. 4,

[0024]FIG. 6 shows the diametric sectional view of the ring vulcanizedinto the rubber bellows,

[0025]FIGS. 7a through 7 c show the individual phases of a secondembodiment for connecting a rubber bellows to a protective cap, namely,

[0026]FIG. 7a shows the perspective view of a ball-and-socket jointwithout the rubber bellows and without protective cap,

[0027]FIG. 7b shows the view from FIG. 7a with a rubber bellows attachedwith a ring vulcanized in with axially projecting teeth,

[0028]FIG. 7c shows the view from FIG. 7b after the protective cap hasbeen put on and after the thermoplastic deformation of the previouslyprojecting teeth,

[0029]FIG. 8 shows the top view of the ring from FIG. 7b, and

[0030]FIG. 9 shows the side view of the ring in the direction of arrowIX in FIG. 8.

[0031] In FIGS. 1 through 6, identical parts are always designated bythe same reference numbers. The ball-and-socket joint 1 according toFIG. 1 intended for being arranged between chassis parts in a motorvehicle is provided with a joint housing 2 and a joint shell 3, arrangedtherein, which surrounds the ball 4 over a large area, the pivot pin 5of the said ball 4 protruding from the joint housing 2.

[0032] According to FIG. 2, this pivot pin 5 is surrounded by a rubberbellows 6 with a protective cap 7, and a ring 8 for holding theprotective cap 7 is vulcanized into the edge area 6 a of the rubberbellows 6, which said edge area concentrically surrounds the pivot pin5. This ring 8 has at least one circular bead 8 b, 8 c on its annularouter side 8 a (see FIG. 6).

[0033] The protective cap 7 is provided on its inner side 7 a with aplurality of projections 9, only one of which is shown in FIG. 2.

[0034] According to FIG. 3, this projection 9 can be bent by means of atool 11, e.g., with a screw driver in the case being shown, radially inthe direction of arrow 12 against the pivot pin 5 and thus in anon-positive and positive-locking manner against the bead 8 b or 8 c ofthe ring 8. As a result, this projection is dug into the material of therubber bellows 6 surrounding the bead 8 b and 8 c, in which material thering 8 is vulcanized. As a result, the protective cap 7 is seatedimmovably on the rubber bellows 6, without axial forces having to beapplied to the latter 6 in the direction of the double arrow 13. Sincethe protective cap 7 is now fixed in an oriented manner on the rubberbellows 6, on the one hand, and on the pivot pin 2 [sic-Tr.Ed.], on theother hand, it can follow the particular desired and/or necessaryangular deflection together with the rubber bellows 6, without any forcebeing applied on the ball-and-socket joint 1 whatsoever.

[0035] In the case being shown, the ring 8 has a wave-shaped crosssection. As a result, a plurality of beads 8 b and 8 c are formed on itsouter side, so that the projections 9 can engage one bead or the other,8 b or 8 c, as desired, and can dig into the rubber material of therubber bellows 6 located in front of them.

[0036] The projections 9 may have any desired shape x and are formed inthe case being shown by the web of T-shaped notches 10, whose web isbent off toward the inner side 7 a of the protective cap 7 and thusforms the projection 9.

[0037] The position of the ring 8 vulcanized into the rubber bellows 6can be clearly recognized from FIGS. 4 and 5. The rubber bellows 6 is incontact with a ring 14 and the annular inner projections thereof withthe outer circumference 5 a of the pivot pin 5 in a frictionally engagedmanner (see FIG. 5). At its opposite end, the rubber bellows 6 isprovided with an outer ring 15 (see FIG. 4), which is held in apositive-locking manner on an enclosing ring 16, which is in turn fixedto the joint housing 2, as can be seen in FIG. 2.

[0038] As can be clearly recognized from FIGS. 1 through 3, thissolution guarantees not only a vehicle-oriented connection of the rubberbellows 6 to the protective cap 7, which completely to protects therubber bellows 6 against both the effect of heat and wind movements andstone chips. Reference is made for this purpose to the left-hand half ofFIG. 2, because the right-hand half of the figure shows a cut-away viewin the lower area to expose the enclosing ring 16 of the protective cap7. As a result, the protective cap 7 with its lower edge area 7 b can bemoved up to the meridian plane 17 of the ball-and-socket joint 1. Thelongitudinal symmetry axis of the pivot pin 5 is designated by 18.

[0039] The second embodiment of the present invention is shown in FIGS.7a through 9. Parts that are identical to those in FIGS. 1 through 6 aredesignated by the same reference numbers. In this embodiment, the ring19 vulcanized into the edge area 6 a of the rubber bellows 6 has aplurality of projections 20 on its side facing away from theball-and-socket joint 1, and the said projections 20 pass through theopenings 21 of identical cross-sectional configuration of the protectivecap 7, which were prepared in advance, and after passing through, theyconnect the ring 19 and consequently the rubber bellows 6 to theprotective cap 7 either by mechanical or thermal deformation.

[0040] As can be determined especially from FIGS. 8 and 9, theprojections 20 of the ring 19 are formed by teeth, which are of equalsize, are located at equally spaced locations and engage a correspondinghole pattern 22 of the protective cap 7 when the protective cap is puton. Two different embodiments are possible here:

[0041] According to a first embodiment, the ring 19 may consist of metaland be provided with only a few projections 20, which do, however,extend through the openings 21 of the protective cap 7 over a certainlength, and these projections can be bent over in one of the twopossible directions of deformation, e.g., by means of nippers after theprotective cap 7 has been placed on the rubber bellows 6 and as aresult, they connect the protective cap 7 to the rubber bellows 6 in apositive-locking manner.

[0042] According to a second embodiment, the ring 19 may be made, as canbe seen, of an injection-molded plastic part and vulcanized into therubber bellows 6. After the protective cap 7 has been put on with a holepattern 22 corresponding to the pattern of the projecting teeth 20, theends of the teeth 20 protruding over the surface 7 c of the protectivecap 7 are melted off by a brief and locally limited heating, e.g., bymeans of a resistance wire or induction wire to form a material headextending over the hole pattern 22, and the protective cap 7 is firmlyconnected to the rubber bellows 6 as a result. This solution isassociated with the advantage of a complete protective cap 7 having noperforations 10 (see FIG. 3). Since the protective cap 7 is connected tothe rubber bellows 6 in a vehicle-oriented manner in this case as well,this solution has, moreover, the same advantages as the first embodimentalternative according to FIGS. 1 through 6.

[0043] The rings 8 and 19 may be made of steel or plastic, e.g., PA 66.However, it is also possible to manufacture the ring 8 provided with thebeads 8 b and 8 c from hardened carbon steel.

[0044] The ring 19 provided with the projections 20 according to thesecond embodiment shown in FIGS. 7a through 9 consists either of metal,e.g., for the mechanical deformation of the projections 20, or of aplastic with high heat resistance, such as PA 66, PTFE or PEEK, in orderto melt off the teeth 20 extending through the protective cap 7 in thehole pattern 22 by a brief heating to make them into a rivet head.

[0045] The protective cap 7 advantageously consists of a special steel,hot-galvanized steel plate or a glass fiber-reinforced plastic in orderto protect the rubber bellows 6 from both thermal effects and mechanicalforces.

[0046] List of Reference Numbers

[0047] Ball-and-socket joint 1

[0048] Joint housing 2

[0049] Joint shell 3

[0050] Joint ball 4

[0051] Pivot pin 5

[0052] Outer circumference of pivot pin 5 5 a

[0053] Rubber bellows 6

[0054] Edge area of rubber bellows 6 6 a

[0055] Protective cap 7

[0056] Inner side of protective cap 7 7 a

[0057] Edge area of protective cap 7 7 b

[0058] Surface of protective cap 7 7 c

[0059] Rings 8, 19

[0060] Outer side of ring 8 8 a

[0061] Beads of ring 8 8 b, 8 c

[0062] Projections 9

[0063] T-shaped notches 10

[0064] Tool 11

[0065] Arrow 12

[0066] Double arrow 13

[0067] Inner ring 14

[0068] Inner projection of inner ring 14 14 a

[0069] Outer ring 15

[0070] Enclosing ring 16

[0071] Meridian plane 17

[0072] Longitudinal symmetry axis of pivot pin 5 18

[0073] Teeth 20

[0074] Openings 21

[0075] Hole pattern 22

1. Joint, especially ball-and-socket joint for chassis parts in a motorvehicle, with a joint housing and with a joint shell arranged thereinwith a ball, whose pivot pin protrudes from the joint housing and issurrounded by a rubber bellows with a protective cap, wherein a ring forholding the protective cap is connected to the edge area of the rubberbellows, which said edge area concentrically surrounds the pivot pin,characterized in that on its said annular outer side (8 a), the saidring (8) has at least one bead (8 b, 8 c) and is vulcanized into thesaid edge area (6 a) of the said rubber bellows (6), and that the saidprotective cap (7) is provided on its said inner side (7 a) with aplurality of said projections (9), which can be bent through saidopenings (10) in the said protective cap (7) from the outside againstthe said bead (8 b, 8 c) of the said ring (8) in a non-positive andpositive-locking manner.
 2. Joint in accordance with claim 1,characterized in that the said projections (9) can be bent through saidopenings (10) in the said protective cap (7) from the outside by meansof a said tool (11) centripetally or radially in relation to the saidpivot pin (5).
 3. Joint in accordance with claim 1 or 2, characterizedin that the said ring (8) has a wave-shaped cross section.
 4. Joint inaccordance with claim 1 or 2, characterized in that the said protectivecap (7) completely surrounding the said rubber bellows (6) is providedwith said T-shaped notches (10), of which at least one said web (9) isbent off toward the said inner side (7 a) of the said protective cap (7)and forms a said projection (9).
 5. Joint, especially ball-and-socketjoint for chassis parts in a motor vehicle, with a joint housing andwith a joint shell arranged therein with a ball, whose said pivot pinprotrudes from the joint housing and is surrounded by a rubber bellowswith a protective cap, wherein a ring for holding the protective cap isconnected to the edge area of the rubber bellows, which said edge areaconcentrically surrounds the pivot pin, characterized in that the saidring (19) is vulcanized into the said edge area (6 a) of the said rubberbellows (6) and has a plurality of said projections (20) on its sidefacing away from the said ball-and-socket joint (1), which saidprojections (20) extend through said openings (21) of identicalcross-sectional configuration of the said protective cap (7), which saidopenings were prepared in advance, and connect the said ring (19) to thesaid protective cap (7) after passing through by mechanical or thermaldeformation.
 6. Joint in accordance with claim 5, characterized in thatthe said projections (20) of the said ring (19) are formed by teeth ofequal size spaced at equally spaced locations, which engage a saidcorresponding hole pattern (22) of the said protective cap (7) when thesaid protective cap (7) is placed on.
 7. Joint in accordance with one ofthe claims 1 through 6, characterized in that the said rings (8, 19)consist of steel or plastic such as PA
 66. 8. Joint in accordance withone of the claims 1 through 7, characterized in that the said ring (8)provided with a said bead (8 b, 8 c) consists of hardened carbon steel.9. Joint in accordance with one of the claims 1 through 7, characterizedin that the said ring (19) provided with the said projections (20) inthe said rubber bellows (6) is made of either metal or a plastic withhigh heat resistance, such as PA 66, PTFE or PEEK.
 10. Joint inaccordance with one of the claims 1 through 9, characterized in that thesaid protective cap (7) consists of special steel, hot-galvanized steelplate or a glass fiber-reinforced plastic.